Hearing speech in noisy rooms is difficult for everyone, but children are particularly vulnerable to the deleterious effects of background noise. It is thought that the ability to pull out speech from competing noise depends on how the nervous system recognizes statistical patterns in the target sound (e.g., a speaker's voice) and tracks them while supresing neural responses to the background noise. Specifically, the degree to which the auditory brainstem demonstrates enhanced responses to patterns in the ongoing speech stream relates to the perception of speech in noise. We do not know how auditory training during childhood, such as musical training, may benefit brain systems for hearing speech in noise, despite evidence to this effect in adults. For musical training to enhance the nervous system's ability to profit from regularities in speech would not be surprising given that sound paterns are the building blocks of music, contributing to the perception of tonality, rhythm and meter, and the structural use of musical themes. This project aims to evaluate the developmental impact of musical training during childhood on subcortical brain systems that underlie the ability to hear speech in background noise in children as young as 3 years of age. Specifically, auditory brainstem responses to predictable and variable speech patterns and measures of hearing speech in noise ability will be obtained in children as young as 3 years of age with and without musical training. We hypothesize that children with musical expertise demonstrate increased neural enhancement of predictable speech, compared with children who have not participated in musical training, with this enhancement increasing with both development and years of musical practice. This neural enhancement is observed in musician children in the context of better behavioral performance for hearing speech in noise. Results will improve our knowledge of how auditory expertise shapes sensory processing (e.g., in challenging listening environments) and its impact on how the brain utilizes signal regularities. Results may also contribute to the improved efficacy of educational and remedial programs for children with noise-exclusion deficits, including children with clinical disorders such as developmental dyslexia, specific language impairment and auditory processing disorders. PUBLIC HEALTH RELEVANCE: Results from this project may explain how auditory expertise shapes how the brain deals with speech in noisy environments, such as a teacher speaking in a bustling classroom. Findings may contribute to the improved efficacy of remedial programs for children who have problems hearing speech in background noise, including children who have language-based learning impairment, in addition to laying the groundwork for employing music as a strategy for auditory remediation.